Specialists gather in a top-secret facility to investigate a series of strange deaths on beaches along the Atlantic Ocean. One of the team's scientists examines video evidence to uncover a possible parasitic explanation for the fatalities. But when a determined detective sends her the crazed writings of a mysterious homeless man, the scientist slowly learns that the actual threat may be more dangerous — and far older — than anyone ever imagined. Can she convince her colleagues of the true danger before an ancient force rises from the sea to bring madness and death to all of humanity?